I multiplied the pictures four times. On three of them, putting them Grayscale and RGB after, I casted three different colours: purple, blue and pink. I left Lala pink, cut out the image of Haruna on the pink layer, revealing the purple Haruna on the purple layer. I merged the purple and pink layer and cut out around the two characters to reveal the blue layer. After that, I simply applied a heart and moon brush. Voilą!